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Uncertainty

How much spawning and rearing habitat is available to white sturgeon above and below Bonneville Dam under a range of actual operational conditions? How do these conditions differentially affect spawning success and juvenile growth and survival to the recruitment stage and their entire lifespan?

Nearly all white sturgeon habitat in the Basin is in mainstem reaches of the Columbia and Snake rivers and major tributaries. As a result, every life stage of this species is impacted by conditions in the mainstem. This is an especially critical uncertainty above Bonneville Dam where environmental conditions have led to a lack of recruitment. Managers’ actions to propagate, translocate, or otherwise increase the number of white sturgeon will not be successful if there is inadequate mainstem habitat—and connectivity between habitats—in which they can grow and mature. Also see the Population Structure and Diversity section of this report for other uncertainties related to white sturgeon.